rs1554426994

Positions:

• chr7-124863582-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_015450.3(POT1):​c.314C>T​(p.Thr105Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,461,558 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T105A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: POT1 NM_015450.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 4.92

Genes affected

POT1 (HGNC:17284): (protection of telomeres 1) This gene is a member of the telombin family and encodes a nuclear protein involved in telomere maintenance. Specifically, this protein functions as a member of a multi-protein complex that binds to the TTAGGG repeats of telomeres, regulating telomere length and protecting chromosome ends from illegitimate recombination, catastrophic chromosome instability, and abnormal chromosome segregation. Increased transcriptional expression of this gene is associated with stomach carcinogenesis and its progression. Alternatively spliced transcript variants have been described. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.808

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
POT1	NM_015450.3	c.314C>T	p.Thr105Met	missense_variant	8/19	ENST00000357628.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
POT1	ENST00000357628.8	c.314C>T	p.Thr105Met	missense_variant	8/19	2	NM_015450.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461558 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727084

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Genetic Services Laboratory, University of Chicago

Oct 26, 2016

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 01, 2022

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with multiple primary melanomas (Pastorino 2020); This variant is associated with the following publications: (PMID: 32325837, 28393830) -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 19, 2024

The p.T105M variant (also known as c.314C>T), located in coding exon 4 of the POT1 gene, results from a C to T substitution at nucleotide position 314. The threonine at codon 105 is replaced by methionine, an amino acid with similar properties. This variant has been identified in an individual with multiple primary melanomas who tested negative for mutations in CDKN2A and CDK4 (Pastorino L et al. Cancers (Basel), 2020 04;12). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Tumor predisposition syndrome 3 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 09, 2023

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 105 of the POT1 protein (p.Thr105Met). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with multiple primary melanomas (PMID: 32325837). ClinVar contains an entry for this variant (Variation ID: 436391). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt POT1 protein function with a negative predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Uncertain	0.085	D
BayesDel_noAF	Benign	-0.12
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.57	D
Eigen	Uncertain	0.67
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.94	D
M_CAP	Benign	0.049	D
MetaRNN	Pathogenic	0.81	D
MetaSVM	Benign	-0.76	T
MutationAssessor	Uncertain	2.3	M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Benign	-1.4	N
REVEL	Benign	0.15
Sift	Uncertain	0.0050	D
Sift4G	Uncertain	0.0040	D
Polyphen		1.0	D
Vest4		0.72
MutPred		0.58		Gain of sheet (P = 0.0149);
MVP		0.60
MPC		1.9
ClinPred		0.97	D
GERP RS		5.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.32
gMVP		0.78

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1554426994; hg19: chr7-124503636; COSMIC: COSV62932243; COSMIC: COSV62932243;